Search PubMed⌕ Search

Biomedical subjects

E Suzuki

Publications and source records attributed to E Suzuki.

At least 325 records · Page 18Linked to original sources
PubMed1991

Identification of a genomic region that complements a temperature-sensitive, high CO2-requiring mutant of the cyanobacterium, Synechococcus sp. PCC7942.

In a temperature-sensitive, high CO2-requiring mutant of Synechococcus sp. PCC7942, the ability to fix intracellularly accumulated inorganic carbon was severely impaired at non-permissive temperature (41 degrees C). In contrast, inorganic carbon uptake and ribulose-1.5-bisphosphate carboxylase activity in the mutant were comparable to the respective values obtained with the wild-type strain. The mutant was transformed to the wild-type phenotype (ability to form colonies at non-permissive temperature under ordinary air) with the genomic DNA of the wild-type strain. A clone containing a 36 kb genomic DNA fragment of the wild-type strain complemented the mutant phenotype. The complementing activity region was associated with internal 17 kb SmaI, 15 kb HindIII, 3.8 kb BamHI and 0.87 kb PstI fragments. These 4 fragments overlapped only in a 0.4 kb HindIII-PstI region. In the transformants obtained with total genomic DNA or a plasmid containing the 3.8 kb BamHI fragment, the ability to fix intracellular inorganic carbon was restored. Southern hybridization and partial nucleotide sequence analysis indicated that the cloned genomic region was located approximately 20 kb downstream from the structural genes for subunits of ribulose-1.5-bisphosphate carboxylase/oxygenase. The cloned region was transcribed into a 0.5 kb mRNA. These results indicate that the cloned genomic region of Synechococcus sp. PCC7942 is involved in the efficient utilization of intracellular inorganic carbon for photosynthesis.

Blotting, Northern↗
PubMed1991

Enhancing effect of mouse peritoneal exudate cells and their products on antibody productivity of hybridoma cells: application of in vivo factors to in vitro culture.

Mouse peritoneal exudate cells induced by casein enhanced in vitro antibody production rate per cell of a hybridoma in co-culture. Culture supernatant of the exudate cells also enhanced three-fold the antibody productivity when added to cultures of a hybridoma at 10% (v/v). Hence the enhancement of antibody productivity by the exudate cells seemed to be caused by soluble enhancing factors secreted by the exudate cells. The exudate cells maximally secreted the enhancing factors when harvested from mice on day 4 of the induction period following the injection of casein. A semi-continuous culture of the hybridoma demonstrated the applicability of the culture supernatant to enhance antibody production by producing a two-fold increase over the control for seven days when supplemented with the supernatant at 5%. Significant amounts of interleukin-6 were detected in culture supernatant of the exudate cells. Interleukin-6 obtained from other sources enhanced the antibody productivity two-fold when added to the hybridoma culture at the concentration of 5 unit/ml. Interleukin-6, therefore, is expected to be one of the principal antibody enhancing factors secreted by the exudate cells. Other interleukins examined, that is, interleukin-1 to -5 did not enhance the antibody productivity.

Animals↗
PubMed1991

Serum interleukin-6 in schizophrenic patients.

We examined serum interleukin-6 (IL-6) in 90 schizophrenic patients in remission and 90 normal controls using enzyme-linked immuno-sorbent assay (ELISA). We found a significant difference in variation between the schizophrenic and the control groups (F = 10.9, P less than .002). The difference in distribution was also statistically significant by Kolmogorov-Smirnov (chi-square = 45.0, P less than .001). Eight patients had aberrantly high serum levels of interleukin-6. Since the higher levels of IL-6 are characteristically found in several autoimmune disorders, our finding suggests a link between schizophrenia and immune response, which could be either autoimmune or a process induced by reactivation of viruses.

Adolescent↗
PubMed1991

Validation of a toxicity testing model by evaluating oxygen supply and energy state in the isolated perfused rat kidney. Single-pass preparation without albumin.

Validation of a toxicity testing model concerning energy metabolism was attempted by evaluating the oxygen supply and energy state in an isolated perfused rat kidney of single-pass preparation without albumin. Perfusion was performed at a temperature of 31 degrees C, flow rate of 11.0 mL/g/min, and pressure of 81-104 mmHg. The perfusate was saturated with 95% O2/5% CO2. After preperfusion for 30 min, the redox states of cytochrome aa3 and c and pyridine nucleotides (PN) in the perfused kidney were measured to be stable for 90 min by a scanning reflectance spectrophotometry and surface fluorometry, respectively. During the same period, the contents of ATP and inorganic phosphate (Pi) in the perfused kidney were also measured to be stable by 31P-NMR spectroscopy. The oxygen supply to the cell was more than the amount required for the basal metabolism of the cell. For assessment of the effects of chemical agents on the renal cell metabolism, this preparation of the perfused rat kidney was considered to have several advantages, despite some of its inherent limitations in the function of the kidney.

Adenosine Triphosphate↗
PubMed1991

Differential effects of atrial natriuretic peptide and dopamine on urinary protein excretion in chronic glomerulonephritis.

1. To examine whether or not atrial natriuretic peptide-induced proteinuria simply results from increases in urine flow or glomerular filtration rate, we infused dopamine (1 microgram min-1 kg-1) and alpha-human atrial natriuretic peptide (0.025 microgram min-1 kg-1) into nine patients with chronic glomerulonephritis and nine essential hypertensive patients without renal damage, and compared the effects of the two agents on renal function and urinary protein excretion. 2. In patients with chronic glomerulonephritis, dopamine infusion significantly increased urinary sodium excretion (+59%), renal blood flow (+20%) and creatinine clearance (+14%). However, urinary protein excretion was not changed. Addition of atrial natriuretic peptide to the dopamine infusion further increased urinary sodium excretion and maintained creatinine clearance at the same level. In contrast to the infusion of dopamine alone, atrial natriuretic peptide markedly increased urinary protein excretion (77 versus 229 mg min-1 m2, P less than 0.02). Furthermore, the addition of atrial natriuretic peptide elevated the urinary protein/creatinine ratio (1.55 versus 5.35, P less than 0.05), while dopamine alone did not (1.55 versus 1.45, not significant). 3. In essential hypertensive patients, dopamine and dopamine plus ANP showed renal effects similar to those of chronic glomerulonephritis; however, the urinary excretion of protein was not changed significantly. 4. These results suggest that atrial natriuretic peptide may increase urinary protein excretion mainly by increasing the permeability of the damaged glomeruli to protein rather than by simply increasing urine flow or glomerular filtration. Possible mechanisms underlying the proteinuria-increasing effects of atrial natriuretic peptide are discussed.

Adult↗
PubMed1991

Role of endothelium-derived relaxing factor in endothelin-induced renal vasoconstriction.

It has been suggested that endothelin (ET) induces the release of endothelium-derived relaxing factor (EDRF). To explore the possible modification of ET-induced renal vasoconstriction by EDRF, we examined the effects of ET on renal vascular resistance (RVR) and urinary Na excretion (UNaV) in the rat isolated perfused kidney before and after the administration of EDRF antagonists. ET at 2 x 10(-11) to 2 x 10(-9) M elevated the RVR in a dose-dependent fashion, whereas it lowered the RVR at 10(-12) M. ET decreased UNaV significantly only at the highest dose. Acetylcholine at 10(-7) M decreased the RVR (-19%, p less than 0.05) and increased UNaV (+177%, p less than 0.05). In contrast, a soluble guanylate cyclase inhibitor, methylene blue (MB; 10(-5) M), increased the RVF by 30% (p less than 0.05) and decreased UNaV by 48% (p less than 0.05). Pretreatment with MB significantly augmented the ET-induced renal vasoconstriction by about 80%. However, UNaV was not influenced significantly. ET increased the urinary excretion of prostaglandin (PG) E2 and 6-keto-PGF1 alpha. Pretreatment with indomethacin (10(-5) M) also significantly enhanced the response of RVR to ET by 60% without changing UNaV. These results suggest that the vasoconstrictor, but not the antinatriuretic, activity of ET may be modified by the release of EDRF and prostacyclin.

Animals↗
PubMed1991

Time- and dose-dependent induction of invasive urinary bladder cancers by N-ethyl-N-(4-hydroxybutyl)nitrosamine in B6C3F1 mice.

A sequential investigation of N-ethyl-N-(4-hydroxybutyl)nitrosamine (EHBN) bladder carcinogenesis was performed in male B6C3F1 mice maintained ad libitum on tap water containing 0.025% EHBN for 4, 12, 20, 28 and 36 weeks. A total of 81 invasive tumors, comprising 55 squamous cell carcinomas (SCCs) (68%), 25 transitional cell carcinomas (TCCs) (31%) and 1 adenocarcinoma (1%) were found. Of these, 23 (22 SCCs and 1 TCC) demonstrated invasion to the prostate, 3 metastasized to the lung, and 2 spread by peritoneal seeding. The anaplastic grade and extent of invasion of the SCCs significantly exceeded those of the TCCs. The results suggested a histogenetic pathway from simple dysplasia through papillary or nodular dysplasia and/or carcinoma in situ to eventual development of invasive carcinomas.

Animals↗
PubMed1991

Effects of atrial natriuretic peptide on urinary protein excretion in mesangial proliferative glomerulonephritis.

Atrial natriuretic peptide (ANP) increases proteinuria in primary glomerular disease. To study whether mesangial proliferation influences this effect, we infused alpha-human ANP at 25 ng/kg/min for 40 min into 6 patients with minor glomerular abnormalities (MGA), 10 with focal glomerulonephritis (FGN) and 8 with diffuse glomerulonephritis (DGN), and determined its renal effects. ANP significantly increased urinary excretions of Na and protein in all groups. Increases in urinary Na excretion were comparable among the groups (about + 200%), while increases in urinary protein excretion were greater in DGN than in the other two groups (DGN + 153 micrograms/min/1.73 m2, MGA + 77 micrograms/min/1.73 m2, FGN + 70 micrograms/min/1.73 m2). This increase was not related to the preinfusion level of proteinuria. Furthermore, the ratio of urinary protein to creatinine was significantly elevated by about 250% in the three groups. Thus, ANP seems to increase the permeability of the glomerular basement membrane to protein, particularly in patients with DGN, possibly through mesangial proliferation and the associated changes in adjacent tissues.

Adolescent↗
PubMed1991

Role of endogenous atrial natriuretic peptide in regulating sodium excretion in spontaneously hypertensive rats. Effects of neutral endopeptidase inhibition.

To explore whether pathophysiological plasma levels of atrial natriuretic peptide (ANP) actually involve sodium excretion in spontaneously hypertensive rats (SHR), we examined the in vivo and ex vivo effects of ANP and an endopeptidase inhibitor, thiorphan, on urinary sodium excretion and the elimination rate of ANP. We found the following: 1) The basal plasma ANP level was higher in 16-week-old SHR than in Wistar-Kyoto (WKY) rats (109 +/- 10 [SEM] versus 63 +/- 4 pg/ml, p less than 0.001). Thiorphan (30 mg/kg i.v.) significantly increased plasma ANP by 60% in both SHR and WKY rats. However, increases in urinary sodium excretion (+290% versus +130%, p less than 0.05) and cyclic GMP (+160% versus +60%, p less than 0.05) were greater in SHR than in WKY rats. Urinary excretion of ANP was markedly increased by thiorphan, and its increase was greater in SHR than in WKY rats. 2) The thiorphan-induced natriuresis was substantially attenuated by antiserum for ANP but not by a bradykinin receptor antagonist. 3) Isolated SHR kidneys excreted 50% less sodium than WKY rat kidneys at perfusion pressures of 100 and 160 mm Hg (p less than 0.05). Urinary sodium excretion was increased at the perfusate ANP level of 100 pg/ml, a concentration similar to the SHR plasma ANP (+70% at 160 mm Hg). 4) After bolus administration of ANP to the isolated kidney, the ANP concentration of the recirculating perfusate decreased rapidly in a log-linear fashion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Pharmacokinetics of caffeine and its metabolites in horses after intravenous, intramuscular or oral administration.

The pharmacokinetics of caffeine (CAF) and its metabolites, dimethylxanthines, were examined in horses administered 2.5 mg/kg of CAF intravenously (i.v.), intramusculary (i.m.), or orally (p.o.). The plasma samples were extracted by Extrelut and the concentrations of CAF and metabolites were determined by high performance liquid chromatography (HPLC) with a short column. The pharmacokinetics of CAF after bolus i.v. injection were described by the assumption of a two-compartment model, and those of CAF after i.m. or p.o. administration were done by the assumption of a one-compartment model. The biologic half lives of CAF were 15.5, 18.6, and 16.4 h after administering i.v., i.m. and p.o., respectively. The extent of the bioavailability of the p.o. administration was determined as 1.04 times the dose. The differences in pharmacokinetic parameters were not statistically significant among administration routes. A straight correlation existed between the logarithms of body weights of different species of animals and those of their biologic half lives of CAF. Therefore, the biologic half life of CAF in an animal might be predictable as a function of its body weight.

Administration, Oral↗
PubMed1991

Detection and identification of loline and its analogues in horse urine.

Several kinds of loline-type alkaloids, norloline, loline, N-acetylnorloline, N-acetylloline, N-formylnorloline, N-formylloline and N-methylloline were detected in the urine of race-horses. Furthermore, a new compound of the alkaloids, N-senecioylnorloline, was also found and identified. These compounds were mainly identified by means of gas chromatography-mass spectrometry (GC-MS) and gas chromatography-fourier transform-infrared spectrometry (GC-FT-IR). A certain plant of Gramineae containing four kinds of loline-type alkaloids was found in a bale of hay used for the horse forage. The taxonomic feature of the plant was different from known plants containing loline-type alkaloids. The common fragmentation of loline-type alkaloids under electron ionization was briefly discussed.

Alkaloids↗
PubMed1991

[Interdigestive contractile characteristics of canine pylorus and gastroduodenal regions].

Interdigestive contractile activity of the gastric body, antrum, pyloric ring and duodenum was recorded by means of chronically implanted force transducers in 5 conscious dogs. In accordance with interdigestive phase III contractions in the gastroduodenal region, a burst of strong contractions and remarkable relaxations were observed to occur in the pyloric ring. In accordance with the intense phase III contractions in the antrum, the pyloric ring was relaxed and duodenal contractions declined and ceased as if the passage of gastric contents expelled by the strong contractions in the antrum were being done smoothly. With the termination of the antral contractions, it was observed that the duodenal contractions were initiated and followed immediately by tonal increase in the pyloric ring super-imposed with phasic contractions. These coordinated contractions between the pyloric ring and the duodenum appear to prevent reflux of duodenal contents to the stomach. Bilateral vagal cooling blockade abolished this coordination. As the gastric contractions ceased completely during vagal cooling blockade, irregular phasic contractions were initiated and no relaxation was observed on the pylorus. In conclusion, the pyloric ring is a true functional sphincter which regulates gastric emptying and prevents reflux from the duodenum in the interdigestive state, and these coordinated contractions are regulated by the vagal nerves.

Animals↗
PubMed1991

Comparison of absorption of erythorbic acid and ascorbic acid in guinea pig small intestine.

Both the ascorbic acid (AsA) and erythorbic acid (ErA) absorption in the small intestine of guinea pigs were determined by the perfusion of the small intestine using isotonic phosphate buffer recycled in situ. The absorption rate of AsA in the small intestine of guinea pigs was higher than that of ErA; however, Km of AsA absorption was lower than that of ErA in normal guinea pigs. In AsA-deficient guinea pigs, the absorption rates of both AsA and ErA were higher than those in normal ones. The absorption of AsA and ErA in the small intestine of guinea pigs was inhibited by ouabain. Furthermore, AsA and ErA inhibited each other's absorption. Based on the results, the net amount of the absorbed ErA in the small intestine may be lower than that of AsA, and ErA absorption mechanism seemed to be similar to that of AsA. The absorption rate of both AsA and ErA in the small intestine of guinea pig might be dependent on the AsA level in the tissues.

Animals↗
PubMed1991

[A case of isocyanate-induced hypersensitivity pneumonitis and a compression-air mask thought to be effective in its prevention].

A 41-year-old paint sprayer, who had worked with polyurethane paint since the spring of 1989, developed exertional dyspnea and dry cough and entered hospital on December 4, 1989. Plain chest X-ray film and a computed tomogram of the lung revealed diffuse micronodular shadows in both lower lung fields. DLco was shown to be significantly decreased in a pulmonary function test. A sample of bronchoalveolar lavage fluid showed increased T lymphocytes and a decreased CD4/8 ratio. A lung biopsy specimen revealed alveolitis, but neither Masson body nor granulomas were seen. Serum antibody specific to TDI-HSA was detected, and an environmental provocation test was positive. From these results, the patient was diagnosed as having isocyanate-induced hypersensitivity pneumonitis. We advised him to wear a compression-air mask when he worked, because he did not want to quit his job. Respiratory symptoms have not been seen since then, but careful observation was thought to be necessary. The involvement of type III humoral and type IV cellular immunity was suspected in this case.

Adult↗
PubMed1991

Effects of atrial natriuretic peptide on endothelin-induced vasoconstriction and intracellular calcium mobilization.

Mechanisms for the antagonistic action of atrial natriuretic peptide (ANP) toward endothelin were studied. We examined the effects of ANP on endothelin-induced vasoconstriction in isolated perfused kidney and the elevation of intracellular free calcium concentration using Fura-2 in cultured rat vascular smooth muscle cells (VSMC). Endothelin produced an increase in renal vascular resistance in isolated perfused kidney (2 x 10(-10) mol/l, +109%; P less than 0.01). ANP completely abolished renal vasoconstriction induced by endothelin. Endothelin produced a biphasic elevation in intracellular calcium concentration in the VSMC. Ethyleneglycol-bis-(beta-amino-ethylether)-N,N,N',N'-tetr aac etic acid (EGTA; 3 mmol/l) or nicardipine (10(-8) mol/l) decreased the sustained elevation of intracellular calcium concentration by 10(-8) mol/l endothelin to the basal level (endothelin, +15% versus EGTA + endothelin, -1%; P less than 0.05; endothelin, +18% versus nicardipine + endothelin, +5%; P less than 0.01). Pretreatment with 10(-6) mol/l ANP suppressed neither the peak phase of intracellular calcium concentration elevation (endothelin, 10(-8) mol/l, +35% versus endothelin + ANP, +31%; not significant) nor the sustained phase of intracellular calcium concentration elevation (endothelin, 10(-8) mol/l, +21% versus endothelin + ANP, +16%; not significant). ANP markedly increased the production of cyclic 3',5'-guanosine monophosphate (cGMP) in the VSMC (ANP, 10(-6) mol/l, +1100%; P less than 0.01). However, endothelin did not influence cGMP production in the presence or absence of ANP. ANP may antagonize the vasoconstrictive action of endothelin through an effect on the steps subsequent to the mobilization of intracellular calcium in the pathway of vascular smooth muscle contraction.

Animals↗